So, today I went to Red Lodge for my 3rd time. On my last run of my last time, which was the 7th, I felt super good/confident and just more comfortable, atleast on the easiest runs. Anyways I went today and I went on harder runs and I don't know why but I felt super unbalanced, unstable, and kept feeling like I was about to catch an edge, which I did do ALOT! Was this because I was really sick not long ago, and I'm not fully normal again, or am I just nervous I was on a bigger run, or what? Please just tell me what you think, thanks!

The eustachian (say "you-STAY-shee-un") tubes connect the middle ears camera to the back of the throat. The tubes help the ears drain fluid. They also keep air pressure in the ears at the right level.

When you swallow or yawn, the tubes open briefly to let air in to make the pressure in the middle ears equal to the pressure outside of the ears. Sometimes fluid or negative pressure gets stuck in the middle ear. The pressure outside the ear gets too high. This causes ear pain and sometimes trouble hearing.

See a picture of the eustachian tube camera.
What causes blocked eustachian tubes?

Swelling from a cold, allergies, or a sinus infection can keep the eustachian tubes from opening. This leads to pressure changes. Fluid may collect in the middle ear. The pressure and fluid can cause pain. You also can have ear pain from changes in pressure while you are flying in an airplane, driving up or down mountains, or scuba diving. Fluid in the ear can lead to an infection (acute otitis media). Young children have a high risk of ear infections, because their eustachian tubes are shorter and more easily blocked than the tubes in older children and adults.
What are the symptoms?

Blocked eustachian tubes can cause several symptoms, including:

Ears that hurt and feel full.
Ringing or popping noises in your ears.
Hearing problems.
Feeling a little dizzy.
A fever, which can be a sign of an ear infection.

that and riding steeper slopes is harder. it forces you to turn by following your front foot instead of swishing your back foot.

It could have been a lot of things, but I'll suggest what I would figure are the two most probable. First, you were on some new terrain and probably weren't as relaxed as you might normally be, and steeper is harder. Second, you may have tired legs from other activities or multiple riding days and just not had it. Don't feel too bad though since we all have off days.